import java.util.Scanner;

/**
 * 求解立方根
 */
public class CubicRoot {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            double num = scanner.nextDouble();
            double min = 0;
            double max = num;
            double mid = 0;
            while ((max-min) > 0.001) {
                mid = (max+min)/2;
                if (mid * mid * mid > num) {
                    max = mid;
                } else if (mid * mid * mid < num) {
                    min = mid;
                } else {
                    max = mid;
                    break;
                }
            }
            System.out.printf("%.1f\n", max);
        }
    }
}
